It's about the same as with Excel, but maybe somewhat easier. You can write a rather simple VBA-module, that (depending on the system date, or on values you fill in in a form) calls the import-spreadsheet functionality (docmd.<macroname> parameter1 ... parametern) in a loop. Every pass through the loop imports one file. The coding inside the loop determines the parameters; most of them are fixed, only the full filename is different.

It shouldn't take more than a few hours work for any MS Access programmer to create the application.

Hope this helps.